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Discharge battery to under 8% every 20 cycles
6735 24 2014-12-13
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ciprianboboc
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why are we supposed to discharge the battery to under 8% every 20 cycles?As far as I know, there's no memory effect on lipo batteries.
Also what do they mean by "discharge statically"? leave the battery out of Phantom for a few days?
2014-12-13
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away-point
lvl.4

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I think that 8% level is more about keeping the "smart battery" calibrated to the current battery state/capacity, than about battery life/health.  In fact, some argue not to run the battery down that low, as it may hurt the battery.    I don't know for certain, but I generally try to avoid running down that low.

Apparently, recent battery firmware is designed to automatically discharge a battery to around 50% after sitting for 10 days, because sitting full charged for long periods shortens a battery's life.  I for one am not crazy about this, for a couple of reasons in particular.
2014-12-13
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Autumn
First Officer

China
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You're right , there's no memory effect on lipo batteries
So it seems that the 8% level method is mainly for Smart Batteries
2014-12-15
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HermosaDrones
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Autumn, is there a "best practice" for discharging them?
2015-1-20
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johnwarr.email
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Where do you get the do not use once the battery reaches 80% remaining life from ?
The manual shows the way to test battery life and says when it reaches 0% it is unusable.  
2015-1-21
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tassanilla
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Boy, I'm telling you, as a newcomer I'm feeling like I'm being pulled in two different directions.  Do I need to become an aeronautical engineer to fly this thing or do I just need a BS grinder to sift thru all the "facts" flying around!  I thought that holding the button for 10 seconds until the button LED flashes WAS a load test for the battery.

Somebody tell me simply, do I follow the Sandal or the holy Gourd?!?
2015-1-21
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johnwarr.email
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I just fly the thing and go by what it says in the manual about battery life and testing.
My 3 batteries are coming up for the 20th charge each, and then I will do the drop to 8% and recharge.
Never had any battery troubles since I bought my V+ in July, apart from the "not enough power to return home" message that I put down to the dynamic home point feature not working correctly on one flight.
2015-1-21
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Tony
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I've got 5 batteries. They all have over 30 charges each according to the software assistant. When they each hit their 20th charge cycle I did as DJI instructs and rode them dry. I chose to go beyond the 8% mark and I actually drained them to 0%. As mentioned, I am now at 30 cycles each and they each currently show an overall life of 90-92% left. So, I am a firm believer in the "discharge every 20 cycles" instruction. It is working for me so far.
2015-3-6
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Tony
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Tony@CVP Posted at 2015-3-7 01:55
I've got 5 batteries. They all have over 30 charges each according to the software assistant. When t ...

I should also add that there is not a single sign of swelling in any of the 5 batteries. The are still giving me 15-19 minutes of air time as well. Just as good as the day I got them.
2015-3-6
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crash1sttime
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Just reached 20 discharges, the manual says to run them to 8% or until they dont turn on anymore,

I held the phantom and ran the battery down to 0%, it took about 10 minutes of running at full pelt to get that low after it reached 15% and auto landed, just think if it didnt auto land and power off at 15% you could get another 10 minutes or so of flight.

Seriously need a way to override the auto land or at least adjust the battery levels.
2015-3-6
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dCon0ne
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Discharging the battery down to 8%, like they say above, is not for a memory thing, (like the old Ni-Cd).  It's more for keeping the 6 Cells Voltage Balanced.  So that ALL 6 cells charge up to the same voltage, and when the Battery is discharge, Each Cell in the package, should be a 3.1v.  

If you want to learn more about Li-Po Batteries,  Go read the RC Model Car forums, their the ones that have been using Li-Po's the longest.
2015-5-15
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roy
First Officer

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Cycling the battery after 20 charges help to establish longer life for your Lopo battery. These type of batteries after being run  and down by being charged and discharged in the quads have a tendiency to establishing a memory at the low point which is somewhere between 20-30 percent when you land your quad. After a while the lipo battery with think this is the low point of the battery and establish a memory at that point tubs shortening the life of the battery. But by cycling the batter to 8 %  which is well below the 20-30 percent when flying it tells the battery where it true low point is and thereby extending the life of the lipo. This is done after 20 cycles to interrupt the 20% low end usage and establish the  bottom end discharge. Makes sense to me. Works the same w at with laptop batteries too. You leave the plugged in to AC all the time the after awhile the battery only remembers the high charge and thus quits working because it hasn't been cycled and it looses its memory for the low end discharge.

Cycle that battery after 20 usages to help extend its life. If you leve it in the quad and turned on after a couple of hours it will dr aim. Faster to fly  around the back yard at low altitude to drain it some. Careful not to go to far and boom down she wil come.
2015-5-16
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lloyd.lively
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I have one of my batteries that has developed a sort of memory. I did the deep cycle recharge flew it around until it got down to about 5%. Then charged it. Most times I will get to about 20% and then land it and swap out batteries. Now that battery will say it's charged to 100%, take up the drone and about 75% it drops to less than 30%.  I've done the recharge twice on it now and no improvement even after the last update.
2016-1-13
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Northofthe49th
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Likely time for a new battery, check the cell voltages, you will likely find one of them to be quite different,  have one that is freaking out now at 30%.
If stored full charge for any length of time (the book I believe says 10 days or more) can run in them) could harm them and cause them to swell.
2016-1-13
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DJI-Dave
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Yep sounds like you need a new battery.
2016-1-14
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fans1e2e5a9d
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tassanilla Posted at 2015-1-21 07:20
Boy, I'm telling you, as a newcomer I'm feeling like I'm being pulled in two different directions.  Do I need to become an aeronautical engineer to fly this thing or do I just need a BS grinder to sift thru all the "facts" flying around!  I thought that holding the button for 10 seconds until the button LED flashes WAS a load test for the battery.

Somebody tell me simply, do I follow the Sandal or the holy Gourd?!?

You certainly need to "manage" your LiPo batteries in order to maximise the life you can expect from them longer term, and, you need to take care how you store them also.  It is also worthwhile to "exercise" the batteries every once in a while during periods you do not get extensive use from the drone (e.g. during periods of bad weather, winter, periods where high winds make flight relatively unsafe, or when work or other commitments keep your drone grounded, etc.).  I always store my batteries at "storage charge" in LiPo safe cases, and at room temperature.  IF I see a period of a lack of use I will cycle the batteries in the garage or in a large room in the house just to take the batteries down to  a low charge, then I allow them to cool a bit and then take them up to storage level again.  This keeps the batteries healthy as opposed to leaving them for a long period of time, suddenly charging them up after that long period and giving them a rigorous flight after that long period of non-use.  Also, ALWAYS monitor your cell voltages in the app to ensure that there are no wild deviations from cell to cell, and never attempt to recharge a "hot" battery.  Discharging the batteries in the garage (images attached).  You do not need to be an aeronautical engineer, as you said (!), but,owning and flying a drone is a responsibility , it is potentially dangerous to others and yourself if abused, so some very simple tasks/ routines like battery management do go a long way.
15195864364271370996736.jpg
1519586480563314900021.jpg
2018-2-25
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Jenee 2
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Tony@CVP Posted at 2015-3-6 09:55
I've got 5 batteries. They all have over 30 charges each according to the software assistant. When they each hit their 20th charge cycle I did as DJI instructs and rode them dry. I chose to go beyond the 8% mark and I actually drained them to 0%. As mentioned, I am now at 30 cycles each and they each currently show an overall life of 90-92% left. So, I am a firm believer in the "discharge every 20 cycles" instruction. It is working for me so far.

I have 3 batteries and they have never been below 30%. I always bring them up to storage if I won't be flying for a week or more but if I am flying again within a few days then I fully charge them. They all have around 40 to 45 charges and are all showing a life of 100%.
I know what DJI suggest but having used lipos for over 10 years, my experience with model aircraft has shown me that the batteries that don't last and/or puff are those that have been flown to less than 20%.
2018-2-25
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solentlife
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Guys ... check out the dates of the original thread .... its near 4 years old ...

Near all the posts above yours are old hat and dead dog now. People are far wiser and informed.

There is now no reason to do a discharge every 20 cycles ... but it can be beneficial at various times just to 'recalibrate' the chip on the board. Claims of balancing cells is 'hogwash' .... the battery control board terminates any balancing too early whether at bottom or top end of charge cycles.

One of the posts back in 2015 even says : "Discharging the battery down to 8%, like they say above, is not for a memory thing, (like the old Ni-Cd).  It's more for keeping the 6 Cells Voltage Balanced. "

Since when was there 6 cells ??

Nigel
2018-2-26
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Eric13
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crash1sttime Posted at 2015-3-6 11:05
Just reached 20 discharges, the manual says to run them to 8% or until they dont turn on anymore,

I held the phantom and ran the battery down to 0%, it took about 10 minutes of running at full pelt to get that low after it reached 15% and auto landed, just think if it didnt auto land and power off at 15% you could get another 10 minutes or so of flight.

Never fully discharge Lipos!
2018-2-26
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solentlife
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Eric13 Posted at 2018-2-26 00:55
Never fully discharge Lipos!

DJI battery FW terminates any discharge at 3.0V per cell but in fact uses the total 12V of the pack ...

People claim that the chip determines individual cells for this - sorry but that's rubbish .... I know from own personal observations that is not true.

I did a discharge test on two completely different P3 batterys and some cells dropped BELOW 3.0V before board terminated discharge ... but total was 12.0V

I advise people NOT to go below 8% - because then charger may have difficulty reviving the pack ... I know from the above. Luckily I have worked with LiPo's for many years and they are still in service.

Nigel
2018-2-26
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Nebicaneser
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my batteries after 62 Times charged



only 3 hard discharges each 20 cicles

1st hard discharge : about 12%  temp 48º
2nd hard discharge : about 7% temp 52º
3rd hard discharge : about 4% temp 30º

2018-2-26
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Nebicaneser
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dont sure if i did it right
2018-2-26
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Nebicaneser
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is good 4177 mAh at 95% battery from 4376 mAh total capacity ?
2018-2-26
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Nebicaneser
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PD : this battery never did a automatic discharge
2018-2-26
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solentlife
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Full charge of a DJI pack is 4.35V per cell ... (Lithium Polymer High Voltage) ... commonly termed LiHV ... as against a standard LiPo of 4.20v per cell full charge.

There is no reason why a LiHV should not charge to full 4.35V per cell - even when old and tired.  Its the power delivery and voltage sag that is the age problem.

The mAh calculation you see is based on the Chips interpretation of charge rate against time to charge ... and the voltage terminated at. Bit like the instant fuel consumption + fuel tank contents shown on your car data screen. (That's going to upset a few - that comment !! ).

There is always argument about how mAh charge level is determined and leads to some heavy 'breathing' .... but at end of day the old LiPo Fuel Table still holds reasonable once the first 10% of charge is used.

Personally .... I read the mAh on the screen - but my main interest is the voltage shown ... after so many years of using all sorts of batterys for models from Lead Acid in boats through NiCd in flyers and NiMh in radios to LiPo .. LiFe ... LiHV ... its hard to break the habit and to be honest it works !!

I fly and land. I cell check the LiPo's to ensure they are not over discharged by reading Volts ... My DJI - I read the % and that equates to voltage - despite some claims otherwise. If I land a DJI at 30% - I know I'm good to put battery to storage till next time ...

If I am going to leave the batterys for more than a month - I charge up first - then stand them. Then I know I have a few months before they discharge to low level.

I do suggest to people to NOT use the default 10 day Auto Discharge setting unless you are a frequent flyer and batterys are getting good cycling. If as most people they fly maybe 2 .. 3x a week irregularly - then better to set auto-discharge to 2 or 3 days.
Oner Tip : If you have more than one battery .... try to stagger the charge and auto-discharge. That means that your batterys do not start auto-discharge at same time. But this does not relieve you of making sure battery is full charged before any flight. But it reduces the amount of charge required prior flight.

End of 'sermon' !!

I know my view is not held by all ... that's life. I only post based on my and fellow modellers I have personal contact with - experiences and observations.

Nigel
2018-2-26
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